1. Field of the Invention
This invention relates to ink jet printers. More particularly, this invention is concerned with an ink jet printer, wherein a host computer supplies, through device drivers, print commands and print data to an ink jet printer so that they are processed by an MPU (Microprocessor Unit) and an ASIC (Application Specific Integrated Circuit) to thereby control ink jet nozzles, a carrier and a feed motor.
2. Description of the Prior Art
Printers connected to a host machine generally require transmission of various data (reverse data) to the host machine through bi-directional communications according to IEEE1284. Particularly ink jet printers require transmission of reverse data to the host machine at least in a nibble mode.
There proposed is a technology disclosed, for example, in Japanese Patent Laying-open No. H1-142924 (Jun. 5, 1989), etc. in order to meet these requirements due to a standard. In this technology, status signals are sent back to a host machine, under the control of an MPU, through a Centronics (commodity name) of an 8-bit parallel signal line.
In the prior art, however, the MPU suffers from a heavy burden because the reverse data is sent back to the host under the control of the MPU provided in the printer. Accordingly, there has been a necessity of mounting on a printer a high-speed, expensive MPU in order to achieve high-speed processing.